Abstract
This paper presents an overview of wind energy in Portugal and briefly describes the Portuguese Lightning Location System. Some aspects of lightning activity in Portugal are discussed. The method for risk assessment due to lightning flashes to earth is performed by the computer program LPS 2008 developed in Visual Basic by the authors. LIPS 2008 is based on well established standards and on the Rolling Sphere Method. LPS 2008 draws in 3D the most vulnerable points to lightning of a structure. A case study is presented to illustrate the protection measures resulting from this methodology, reducing damages due to lightning effects in power electronics and electrical machines to acceptable levels.

Abstract
The ability to infer user context based on a mobile device together with a set of external sensors opens up the way to new context-aware services and applications. In this paper, we describe a mobile context provider that makes use of sensors available in a smartphone as well as sensors externally connected via bluetooth. We describe the system architecture from sensor data acquisition to feature extraction, context inference and the publication of context information to well-known social networking services such as Twitter and Hi5. In the current prototype, context inference is based on decision trees, but the middleware allows the integration of other inference engines. Experimental results suggest that the proposed solution is a promising approach to provide user context to both local and network-level services.

Abstract
This paper presents a new integrated model for the simulation of wind power generation systems. This model is not only more accurate but also computationally acceptable. It uses pulse width modulation by space vector modulation associated with sliding mode for controlling the converters. Power factor control at the output of the converters is considered in the model. We present a case study showing the harmonic behavior for the current injected in the electrical network, computed by the Fast Fourier Transform. Finally, we draw comparative conclusions between the performance of the matrix and Multi-level converters.

Abstract
Smart environments (e.g., airports, hospitals, stadiums, and other physical spaces using ubiquitous computing to empower many mobile people) provide novel challenges for usability engineers. Firstly, interaction can be implicit and therefore unintentional on the part of its users. Secondly, the impact of a smart environment can influence the collective or crowd behavior of those immersed within it. These challenges lead to requirements for complementary analyses which must be combined with the more typical focus on the interaction between user and device. The paper explores a family of stochastic models aimed at analyzing these features with a particular focus on crowd interaction. Copyright 2009 ACM.

Abstract
This paper investigates the potential impact of increased R&D efforts and structural change in Portugal on labour productivity. Based on existing literature on the relation between R&D expenditures, structural change and productivity, we evaluate the contribution of R&D and hightech industries to productivity over the last 30 years. Our results confirm the importance of business R&D in the medium to high-tech sectors and of public R&D, as they stimulate productivity growth. However, we cannot support the hypothosis that productivity growth was primarily rooted in the development of medium-high technology industries.

Abstract